There are at least three methods to run a diesel engine on biofuel using veggie oils, animal fats or both. All 3 are utilized with both fresh and used oils.

1. Use the oil simply as it is-- typically called SVO fuel (straight grease);

2. Mix it with kerosene (paraffin) or petroleum diesel fuel, or with biodiesel, or mix it with a solvent, or with gas;

3. Convert it to biodiesel.

The very first two methods sound simplest, however, as so typically in life, it's not quite that simple.

1. Mixing it

Grease is a lot more thick (thicker) than either petro-diesel or biodiesel. The function of blending it or blending it with other fuels is to reduce the viscosity to make it thinner so that it streams more freely through the fuel system into the combustion chamber.

If you're blending veg-oil with petroleum diesel or kerosene (exact same as # 1 diesel) you're still using fossilfuel-- cleaner than many, but still not tidy enough, lots of would state. Still, for every gallon of

grease you utilize, that's one gallon of fossil-fuel saved, and that much less climate-changing carbon in the atmosphere.

People use numerous blends, varying from 10% vegetable oil and 90% petro-diesel to 90% grease and 10% petro-diesel. Some individuals just use it that way, launch and go, without pre-heating it (that makes veg-oil much thinner), and even vegetable oil without pre-heating it, which would make it much thinner.

You might get away with it with an older Mercedes 5-cylinder IDI diesel, which is a very tough and tolerant motor-- it won't like it but you probably won't kill it. Otherwise, it's not wise.

To do it properly you'll require what totals up to an SVO system with fuel pre-heating anyway, ideally utilizing pure petro-diesel or biodiesel for starts and stops. (See next.) In which case there's no need for the mixes.

Blends with different solvents and/or with unleaded gasoline are "experimental at best", little or absolutely nothing is learnt about their effects on the combustion attributes of the fuel or their long-lasting results on the engine.

Higher viscosity is not the only problem with utilizing grease as fuel. Veg-oil has various chemical homes and combustion qualities from the petroleum diesel fuel for which diesel engines and their fuel systems are developed.

Diesel engines are state-of-the-art devices with very accurate fuel requirements, specifically the more contemporary, cleaner-burning diesels (see The TDI-SVO debate).

They are difficult however they'll only take so much abuse. There's no assurance of it, but using a blend of as much as 20% veg-oil of excellent quality is said to be safe enough for older diesels, particularly in summer.

Otherwise utilizing veg-oil fuel needs either a professional SVO service or biodiesel. Mixes and blends are generally a poor compromise. But mixes do have an advantage in cold weather condition.

Just like biodiesel, some kerosene or winterised petro-diesel fuel blended with straight vegetable oil lowers the temperature level at which it starts to gel. (See Using biodiesel in winter season) More about fuel mixing and blends.